We plan to complete a worldwide genetic survey of natural populations of the yellow fever mosquito, Aedes aegypti. By means of gel electrophoresis we are studying 23 gene loci coding for enzymes. To date we have sampled 18 field populations; we hope to add about 10 more. In addition we will initiate cytogenetic studies to determine the extent of naturally occuring chromosome inversions. Finally we plan to complete some biting preference studies with A. aegypti. BIBLIOGRAPHIC REFERENCE: Tabachnick, W.J. and J.R. Powell (1976) Allozymic variation in the yellow fever mosquito, Aedes aegypti. Genetics 83: s75-s76. (Abstract).